1. The Field of the Invention
The present invention relates to the field of dental instruments. In particular, the present invention relates to endodontic files that are used for debriding and cleaning root canals during endodontic procedures. Even more particularly, the present invention relates to flocked endodontic files that are used to remove pulp, necrotic tissue, organic debris, and other potential irritants from root canals in preparation for receiving dental filling materials.
2. The Prior State of the Art
Endodontics is the branch of dentistry that generally deals with infections and diseases of dental pulp. Dental pulp, which is found in the pulp chamber and root canals of the tooth, comprises a vascular tissue that is generally composed of nerve fibers and blood vessels that nourish the tooth during its growth and development. When bacteria gains access to the pulp, either through a fractured tooth or a deep cavity, the pulp becomes infected and will die unless the body is able to repair and heal the pulp. Pulp can also become infected when the tooth suffers from trauma or a periodontal disease.
When the pulp becomes so severely infected or otherwise damaged that it cannot be healed, it is necessary to remove the pulp to relieve the pain and to prevent infection from spreading beyond the tooth. Pulp can either be removed by extracting the tooth or by performing an endodontic procedure, such as a root canal.
During a root canal procedure, the endodontist accesses the root canal and debrides the root canal of potential irritants such as necrotic tissue, pulp, bacteria, bacterial byproducts and other debris. Debridement essentially consists of loosening the potential irritants from the sides of the root canal with an endodontic tool, such as a file, and then flushing the potential irritants out of the root canal with an irrigant. Some irrigants may comprise or are used in combination with antibacterial disinfectants and/or chelators to sanitize the root canal and to dissolve remaining debris.
The final step of performing the root canal procedure, which is known as obturation, involves filling the root canal with a filling material such as gutta percha or amalgam and sealing the filling with a sealer cement to prevent future contamination of the root canal.
One problem with existing methods and devices for performing endodontic procedures, however, is that the anatomy of the tooth makes it difficult to completely clean potential irritants out of the root canal. In particular, the root canal is irregularly shaped, having contoured surfaces, recessed regions and accessory canals. The irregular shape of the root canal prevents existing endodontic files from reaching and abrading the entire surface area of the root canal, thereby leaving portions of live diseased or necrotic pulp and debris undisturbed.
Some existing flexible endodontic files are capable of following the irregular contours of the perimeter surfaces of the root canal. However, even these existing flexible files are unable to completely reach and abrade the recessed regions and accessory canals of the root canal. Accordingly, to provide access to the hard-to-reach regions of the root canal, it is often necessary to xe2x80x9creshapexe2x80x9d or file down the walls of the root canal. This however, is undesirable because it can cause overthinning of the root canal which increases the risk that an endodontic tool, such as a file or an irrigation cannula, will fracture or perforate the walls of the root canal, causing pain to the patient and further complicating the endodontic procedure.
Reshaping is sometimes required to widen narrow passages of the root canal in order to access apical regions and to minimize hydraulic pressures during obturation. However, filing down the walls of the root canal unnecessarily, simply to provide access to recessed regions for debridement is undesirable, not only because it increases the risks associated with overthinning, but also because it increases the time, and hence the cost, associated with performing the root canal. Furthermore, even after reshaping the root canal, existing endodontic files are still sometimes unable to adequately reach and abrade the recessed regions and accessory canals.
Accordingly, there is currently a need in the art for improved endodontic files for debriding root canals during endodontic procedures.
The present invention is directed to improved endodontic files used to debride root canals during endodontic procedures. The improved endodontic files of the invention comprise flocked files for abrading and removing pulp, necrotic tissue, organic debris, and other potential irritants from the root canal structures, including the recessed regions and the accessory canals.
Each of the flocked files of the invention comprises a shank with a periphery surface, and fibers that are flocked or otherwise attached to the periphery surface. In one preferred embodiment, the periphery surface comprises at least one abrading surface segment with edges that are suitable for abrading or filing the walls of the root canal and at least one flocked surface segment over which multiple fibers are dispersed.
The edges of the abrading surface can be formed in any suitable manner, such as, for example, by machining the periphery surface, by twisting the shank, or by depositing abrasive materials such as diamond, ceramic, and metallic particles on the periphery surface. When the edges of the abrading surface are scraped against the walls of the root canal the potential irritants on the walls are loosened. With sufficient scraping by the abrading surface, the walls of the root canal can also be reshaped or filed down.
The flocked surface segment of the flocked file comprises multiple fibers that are also useful for scrubbing and abrading the root canal surfaces. The flocked surface segment may be separated from or overlap the abrading surface segment and may comprise a single continuous flocked surface segment or multiple separated flocked surface segments.
The fibers disposed on the flocked surface segment(s) assist in the debridement of the root canal and are particularly useful for reaching and abrading the hard-to-reach areas, such as the recessed regions and the accessory canals, without requiring unnecessary reshaping and removal of dentin from the root canal. The fibers may be composed of various plastics, metals or any combination thereof. Suitable plastics include, but are not limited to, polypropylene, polyethylene, nylon and polyester. Suitable metals include, but are not limited to, tungsten and titanium.
The fibers may comprise a uniform length or varying lengths with a preferred length within the range from about 0.3 mm to about 3 mm, and more preferably within a range from about 0.7 mm to about 1.5 mm. The diameters of the fibers may also vary, preferably within a range from about 1 Denier to about 15 Denier, and more preferably within a range from about 1.5 Denier to about 10 Denier. It will be appreciated that the length and diameter of the fibers, as well as the texture, flexibility and the density of distribution of the fibers may vary to accommodate different needs and preferences.
The fibers can be attached to the flocked surface segment by any suitable process, such as electrostatic flocking, injection molding, and welding. In one preferred embodiment, the fibers are electrostatically flocked onto the flocked file segment and secured by an adhesive. The adhesive in the preferred embodiment is a flexible and water insoluble adhesive, such as a polyurethane or flexible acrylic adhesive. Flexible adhesives are particularly useful when the fibers are stiff or rigid because it allows the fibers to bend at their points of affixation. It should be appreciated, however, that other adhesives such as epoxies and silicones can also be used.
In some embodiments, the flocked files of the invention also comprise a handle and a tip. The tip may be configured for scraping or cutting, or alternatively, the tip may be blunt. The handle is used to manipulate and move the flocked file within the root canal.
When the flocked file is rotated or moved up and down within the root canal, the fibers brush against and loosen the pulp, necrotic tissue, organic debris, and other potential irritants in the root canal. The fibers of the flocked file are able to loosen the potential irritants in the recessed regions and accessory canals more effectively than existing prior art endodontic files, without requiring unnecessary reshaping of the root canal. The fibers are also useful for carrying the loosened debris out from the root canal, for evenly distributing solutions, and for reducing hydraulic pressures by rupturing trapped air pockets.
In one alternative embodiment of the invention, the periphery surface does not include an abrasive surface segment. Rather, according to this alternative embodiment, the fibers provide the entire utility of abrading and loosening the pulp, necrotic tissue, organic debris, and other potential irritants in the root canal. In such an embodiment, rigid fibers are preferred. However, it should be appreciated that the flocked file may comprise any combination of rigid and flexible fibers.
One skilled in the art will appreciate that flocked files of the present invention are an improvement over the prior art for at least providing a means for reaching, abrading, and loosening the potential irritants in the root canal more effectively than existing files without requiring unnecessary reshaping and overthinning of the root canal. The flocked files of the invention are also an improvement over the prior art files for at least providing fibers to assist in the removal of the loosened debris from the root canal.
These and other benefits, features and advantages of the flocked files of the present invention will become more fully apparent from the following description and appended claims, or may be learned by practicing the invention as set forth below.